The present study was undertaken 1) to investigate the cell specific distribution and expression of GSTO1-1 in healthy human lung, 2) to compare the GSTO1-1 expression patterns in the lung of non-smokers, smokers without obstruction and smokers with variable severities of COPD, 3) to assess whether GSTO1-1 is associated with COPD severity and 4) to analyze whether GSTO1-1 can be detected in airway secretions/induced sputum supernatants, bronchoalveolar lavage fluid (BALF) or plasma. The gene discussed is GSTO1; the disease is chronic obstructive pulmonary disease.